ITEM: E9752L
Questions on HACMP and SCSI-2 Differential...
Question:
We want to have a shared disk. We have 2 580s that we want to make
redundant. We want to have the disk go to the other system when one
goes down. The network address needs to be assumed. The OS would be
on the local disks and the shared disk would be external with the
application VG. If the shared disk goes down, we must have a copy on
the local disks (I assume rootvg...). We would like to know about
syncing if one disk goes down. We need to get all the necessary
hardware or software to make this happen. We are getting a quote to
give to a customer and we need to know all the steps and what HW, SW,
and support we will need to get.
Response:
I told you that you would need HACMP to give you this full
functionality. You want the disk to come up automatically without any
user interaction.
Response:
The customer wants a HACMP configuration with 1GB of shared disk shared
between two servers. They want to have this disk mirrored onto another
disk which is on its own SCSI chain. Here is the configuration that I
laid out for you:
Network:
[]------------------------------------------------[]
| | | |
---"----"--- ---"----"---
| | | |
| | | |
| | | |
| 7013-580 | | 7013-580 |
| RISC System| | RISC System|
| | | |
------------ ------------
The customer wants 2 ethernet adapters (2980) per each RISC for the network.
Hardware:
SCSI-2 Chain:
The customer wants two SCSI-2 (Differential) Chains with 1 2GB Disk in
each chain. These disks will be mirrored across the chains. Here are
the Feature codes and lengths for the cabling and hardware.
Y-Cable Y-Cable
FC 2422 FC 9221 FC 2921 FC 2422
.765m 4.75m 4.75m .765m
[]------ ------[]-------[ ]-------[]------ ------[]
\\ / | \\ /
\\ / --"-- \\ /
| |7204-| |
-----"------ | 215 | -----"------
| |2420| | | Disk| | |2420| |
| ---- | |(2GB)| | ----- |
| | ----- | |
| 7013-580 | | 7013-580 |
| RISC System| | RISC System|
| | | |
------------ ------------
Here is the excerpt from HWSALESMAN of the 7204-215:
7204 MODEL 215
DIFFERENTIAL SCSI-2 CONTROLLER CABLE (\#9221) 4.75 METERS
This cable is required for attaching a 7204-215 External Disk Drive to the
RISC System/6000 SCSI-2 Differential High-Performance I/O Controller (\#2420).
Additional cables may be ordered using feature code (\#2921). Does not include
terminator which is ordered separately.
Here is the excerpt from HWSALESMAN of the 2422:
SCSI-2 DIFFERENTIAL Y-CABLE (\#2422)
The SCSI-2 Differential Y-Cable provides attachment and termination of an IBM
9334 to two separate RISC System/6000 POWERstation or POWERserver systems.
This is particularly desirable in increased availability environments. Each
system will require a Y-cable. The Y-cable will be attached to the cabling
that comes with the IBM 9334 Differential Expansion Unit. One end of the
50-pin Y-cable must be terminated with a SCSI-2 Differential Terminator which
is included with the SCSI-2 Differential Y-Cable feature. The Y-cable is
.765 meter (30 inches) in length.
Response:
You found out that you needed two disk drive instead of one per each scsi chain.
Thus you need to know what the feature code for the device-to-device cable
between the disk drive is.
You need the differential dual port device-to-device cable (FC 9134).
Here is the excerpt from the 7204 Disk drive for this cable:
DIFFERENTIAL DUAL PORT DEVICE-TO-DEVICE CABLE (\#9134) 2.0 METERS
The Differential SCSI Device-to-Device cable is used if more than one
external device is attached. Additional cables may be ordered using feature
code (\#2848). Does not include terminator.
Here is a diagram to illustrate two shared SCSI chains with two disks
on one of the SCSI strings:
----- -----
|7204-| |7204-|
| 215 | | 215 |
| Disk| | Disk|
|(2GB)| |(2GB)|
--"-- --"--
FC 2422 FC 9221 | FC 9134 | FC 2921 FC 2422
.765m 4.75m | 2.00m | 4.75m .765m
[]- ----[]---------[ ]----------------[ ]--------------[]----- --[]
\\ / \\ /
\\ / []- ---[]-----------[ ]--------------[]----- -[] \\ /
| \\ / FC 9221 | FC 2921 \\ / |
| \\ / | \\ / |
| | --"-- | |
---"--------"--- |7204-| ---"--------"---
| |2420| |2420| | | 215 | | |2420| |2420| |
| ---- ---- | | Disk| | ---- ---- |
| | |(2GB)| | |
| 7013-580 | ----- | 7013-580 |
| RISC System | | RISC System |
| | | |
| | | |
| | | |
| | | |
---------------- ----------------
Response:
Support Line: Questions on HACMP and SCSI-2 Differential... ITEM: E9752L
Dated: January 1994 Category: N/A
This HTML file was generated 99/06/24~13:30:52
Comments or suggestions?
Contact us